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Achieving traffic safety with ‘vaccinated’ AVs: where to begin?

Achieving traffic safety with ‘vaccinated’ AVs: where to begin?

6 December 2021

As we take a hands-off approach to driving, road safety becomes an issue of utmost importance for mobility and a pressing priority for ERTICO- ITS Europe. The same is true also for efficiency. Developments in automated technology and ambitious European targets in the field of transport safety and efficiency are crucial in supporting our work in mobility. However, they are not enough, as identifying what makes mobility safe and efficient in a constantly evolving landscape is a task with challenges. The ITS Hamburg 2021 Executive Session ‘Achieving traffic safety: “herd immunity” with vaccinated AVS’, provided an excellent occasion to discuss these challenges and approach questions surrounding road safety within an inventive framework.

A great deal of European research shows that higher levels of autonomous vehicles could improve road safety. But can safety challenges be met in hybrid traffic models? Since we are experiencing a transition phase where the AVs still share the road network with human drivers, the exact safety benefits are still quite difficult to estimate, due to the very large number of unknown parameters. It has often been argued that in mixed settings where vehicles of different levels of automation -or no automation- are operating simultaneously-, there might emerge additional risks related to safety.

These concerns have been at the center of our inspiring discussion during the ITS Hamburg Executive session. Very interestingly, Jane Lappin (Chair, TRB Standing Committee on Vehicle Highway Automation) and researchers from Delft University, Dr. Ir. Simeon C. Calvert, Assistant Professor​, Prof. Dr. ir. Bart van Arem​, borrowed concepts from the health sciences to approach emerging road safety issues with an innovative eye.

Medical scientists have been using various statistical models to estimate and depict the transmission dynamics of infectious diseases and also to quantify the minimum vaccine coverage level needed to effectively curtail or eliminate community transmission of COVID-19.  What if we borrowed these statistical models to assess the required levels of automated vehicles penetration towards achieving improved traffic safety​? In Lappin’s presentation the automated vehicles were treated as ‘vaccinated actors’ having achieved ‘immunity’ to road accidents in a mixed vehicle’s environment. On the road to herd immunity, vaccination speeds the journey, but is that the case for AVs in a mixed environment, and if so, which are the basic ingredients of this ‘vaccine’?

Originally, when we started discussing ‘herd immunity’ in traffic, scientists were claiming that we can achieve safety but also efficiency in mixed scenarios without large AV penetration rates. Today, it appears that the level of AV penetration needed to provide crash protection to human-driven vehicles and significantly improve public safety for people in all vehicles is highly dependent on an additional critical parameter. In my view, it is connectivity that will provide the key ingredient for AVs to act like ‘vaccinated’ safety agents. I would also claim that the same paradigm can be used also for efficiency. In an extension of the same concept, AVs can also act as “vaccinated” efficiency agents.

It is only when the vast majority of autonomous vehicles are also equipped and connected that the potential safety risks could be minimized and efficiency can increase. Cooperative Intelligent Transport Systems that can interact with their environment -other users, vehicles, equipped road infrastructure etc- can be treated as ‘fully vaccinated agents’. Therefore, when examining ‘safety’ infection rates for vehicles, a ‘third’, stronger vaccine dose -that of connectivity- could dramatically increase AVs impact on road safety and efficiency in a mixed setting.

However, even in a setting with fully equipped and connected vehicles, exposure to risks cannot be minimized since several unpredictable factors may reduce the effectiveness of the ‘vaccine’. In this case, the efficiency of the ‘vaccine’ is also depended on a number of other factors. Technological parameters such as the level of automation, but also several canceling factors that emerge in relation to cybersecurity issues, policy regulations, interoperability and standards, issues of public acceptance and level of training of human drivers and users, are crucial factors when determining the minimum vaccine coverage level needed to effectively eliminate road accidents but also increase traffic efficiency. In particular, policy and legal frameworks with regard to automation need to follow a holistic approach addressing liability and litigation issues, leading to harmonization of standards for interoperable systems.

The ITS Hamburg 2021 Executive Session has clearly showed that approaching automation as an integral part of intelligent transport systems and not as an isolated element, would significantly add to any discussions related to models predicting safety levels in a mixed setting. It has also pointed out that cooperative and connected vehicles and infrastructure are the next stage in the automation journey, towards safer and more efficient transportation systems.

Written by Dr. Angelos Amditis, ERTICO Chairman